The present invention relates to the field of production pneumatic tires and is intended for molding and vulcanizing of tires.
Known in the art is a pneumatic tire vulcanizing apparatus (see U.S. Pat. No. 3,550,196,) comprising a series of tire vulcanizing presses mounted in a longitudinal row, each press comprising a mold made up by a top mold section and a bottom mold section received in a steam dome, the mold being locked for a tire vulcanizing or curing period by means of either lever-type or screw-type mechanisms; a diaphragm or bladder withdrawable into the well of the bottom mold section; a plunger mounted on the top mold section and adapted to push the bladder from a cured tire into the well of the bottom mold section and cooperating with the arms of radially movable segments adapted to engage the top bead of the cured tire prior to unlocking of the top and bottom mold sections; a mechanism for removing cured tires from the top mold section, comprising a movable bead ring mounted in the top mold section and vertically reciprocable by means of an individual hydraulic cylinder, and a manipulator movable longitudinally of said row of the vulcanizing presses, carrying means for lifting, moving aside and lowering the top mold sections, as well as for loading green tires into the molds.
The above mentioned known penumatic tire vulcanizing apparatus is not free from a considerable disadvantage arising from the fact that pushing of the bladder from a cured tire into the well of the bottom mold and spreading of the radially movable segments of the means for clamping the top bead of a cured tire prior to removal thereof from the bottom mold section are performed with the help of a plunger (see U.S. Pat. No. 3,097,394,) mounted on the top mold section of the stationary vulcanizing press.
Since the pneumatic tire vulcanizing apparatus consists of a plurality of such stationary vulcanizing presses, and each such press incorporates the said plunger, and, consequently, the drive of this plunger and the control system associated with this drive, the structure of the tire vulcanizing apparatus, as a whole, becomes considerably complicated.
Besides, the plunger with its drive means and the mechanism for removing cured tires from the top mold sections are positioned in an elevated temperature zone heated up by the steam fed to heat the mold during the vulcanizing or curing operation, which affects the performance of the plunger and its drive and presents specific problems in selecting the material of the sealing means.